Resumen
Immunotherapy is beneficial in specific breast cancer types. To monitor the response to immunotherapy, positron emission tomography (PET) is useful. Several criteria to interpret these images are available and it is essential to have knowledge about their characteristics and applications. Furthermore, it is important to recognize imaging patterns of immune-related adverse events. In the metastatic setting in particular, immunotherapy is only administered if the tumor expresses receptors for the specific treatment, for which biopsies are required to determine receptor expression. However, due to the invasive character of the procedure, biopsies are generally not repeated over time and are not performed in multiple lesions. The strength of PET is that it permits whole-body imaging in a noninvasive way. Few studies in humans have been performed up to now. This narrative review summarizes the ongoing research on immunotherapy options for breast cancer and the role of (immuno-) PET in assessing therapy response.